心血管系統(tǒng)建模

1、心血管系統(tǒng)建模心血管系統(tǒng)建模生物醫(yī)學工程 07碩士 付秀泉人體循環(huán)系統(tǒng)組成n心臟n動脈n靜脈n外周血管網絡外周循環(huán)系統(tǒng)體循環(huán)動脈細動脈毛細血管細靜脈靜脈左心室右心房脈管模型重要參數(shù)n阻抗：血液在血管中流動時因其粘滯性而 受到的阻力血管對流動血液的相對阻抗脈管模型重要參數(shù)n容積：血管的彈性令它在受到透壁壓的時 候發(fā)生舒張，改變容積PVC電路模型類比血管模型電路模型血流阻尼R = P/Q電阻 R血流 Q電流 i血壓 P電壓 e體積 V電荷 q血管容積 C = V/P電容C = q/e體循環(huán)的集中參數(shù)模型集中參數(shù)模型典型值Ca2 ml/mmHgCv100 ml/mmHgRa1 mmHg/ml/sec

2、Rv0.06 mmHg/ml/sec下標 a：動脈V：靜脈Pa：動脈透壁壓PV：靜脈透壁壓Pf：心房灌注壓假設血流為0，出現(xiàn)一個系統(tǒng)平均填充壓PmsPa = Pv = Pf = PmsCt為系統(tǒng)總容積Pms =(Vt V0)/Ct)(VaaaVCCCRRPfPmsQWindkessel簡化模型 如果我們把注意力限制在大動脈上，并認為靜脈的壓力是常量，并近似為0，那么可以把外周循環(huán)簡化為Windkessel模型。V：左心房每搏量 T：心跳周期心室模型D1：房室瓣D2：心室-大動脈瓣)()()(tCvVdtVtP心室壓力-容量關系恒定的前端負載和后端負載與大動脈相連心-肺泵單元 右心 左心完整心血

3、管系統(tǒng)電路模型 右心 肺循環(huán) 左心體動脈Pth：胸內壓 體靜脈研究動態(tài)n聯(lián)合助搏器測試的心血管仿真n左心室模型與任意循環(huán)模型的耦合仿真算法n由壓力反射效應調節(jié)的心血管數(shù)學模型Hardware-in-the-loop-simulation of the cardiovascular system, with assist device testing applicationB.M. Hanson et al. J ELSEVIER, Medical Engineering & Physics 29 (2007) 367374nThe paper presents a technique for

4、evaluating the performance of a cardiac assist device prior to in vivo trials by combining physical (mechanical) testing with a numerical, computerised model of a biological system.nThis Hardware-in-the-loop simulation combines a realistic numerical model of the heart and cardiovascular system with

5、a controllable physical heart simulator.Numerical model of cardiovascular systemHeart SimulatornApplying mechanical assistance in the form of direct cardiac compression can increase blood pressure and cardiac output from a weakened heart.nCompared to testing on an animal model, it is possible to per

6、form repeated experiments, all on an identical patient model, in a short space of time, in a non-clinical setting. nCompared with a purely numerical simulation, HIL simulation enabled evaluation of the effect of the real, physical performance of the prototype assist device.Simulation Algorithm for t

7、he Coupling of the Left Ventricular Mechanical Model with Arbitrary Circulation ModelYutaka NOBUAKI et al. Engineering in Medicine and Biology 27th Annual Conference2005, 7632-7635 Cardiovascular dynamics is the result of the nonlinear interactions between the left ventricular mechanical model and t

8、he circulation model, simultaneous calculation of both models by a strong coupling method is necessary to obtain an accurate simulation result.Left Ventricular ModelLV ModelTime-varying Elastance ModelLV Mechanical ModelAdvantage: Easy to realizeDisadvantage: Difficult to incorporate the characteris

9、tics of the ventricular cells and the structure of the LVEasy to incorporate various physiological properties such as myocardial cell orientation,excitation conducting system, mechanical properties, myocardial electrophysiological model and so on.Therefore, it is very effective to use LV mechanical

10、model to analyze various aspects of the cardiovascular dynamics.Left ventricular mechanical modelH : function for calculating the transformationVlv: left ventricular volume.Plv：inner pressure of LVFb： cell contraction forceCirculation ModelCirculation ModelTwo compartment Windkessel modelTwo element

11、 Windkessel modelFinite Element MethodA cardiovascular dynamics simulation system is constructed by a general finite element method solver as a simulator of the left ventricular mechanical model and an existing software as a simulator of the circulation model. Since most of the circulation models ar

12、e expressed by the equation similar to either of these two models, the proposed coupling algorithm is generally applicable, and the model can be easily exchanged.A Mathematic Model of a Cardiovascular System Regulated by the BaroreflexShaohui Chen et al. Proceedings of the 2006 American Control Conference 701-706A dynamic, nonlinear, lumped parameter model of the cardiovascular system coupled with a baroreflex model is presented. The baroreflex is an important internal feedback mechanism in the body whose function i